docs: def diameter(self, H):
          r'''Calculates cooling tower diameter at a specified height, using
          the formulas for either hyperbola, depending on the height specified.
          
          .. math::
              D = D_{throat}\frac{\sqrt{H^2 + b^2}}{b}
              
          The value of `H` and `b` used in the above equation is as follows:
              
              * `H_throat` - H  and `b_lower` if under the throat
              * `H` - `H_throat` and `b_upper`, if above the throat
                          
          Parameters
          ----------
          H : float
              Height at which to calculate the cooling tower diameter, [m]
      
          Returns
          -------
          D : float
              Diameter of the cooling tower at the specified height, [m]
          '''
          # Compute the diameter at H
          if H <= self.H_throat:
              # Height relative to throat height
              H = self.H_throat - H
              b = self.b_lower
          else:
              H = H - self.H_throat
              b = self.b_upper
          R = self.D_throat*(H*H + b*b)**0.5/(2.0*b)
          return R*2.0